1. Field of the Invention
The present invention relates to a sub-muffler incorporated into an exhaust system of an automobile.
2. Description of Related Art
A sub-muffler integrated into an exhaust system of an automobile is often housed and disposed in a floor tunnel section that is formed so as to extend in the front/back direction of the vehicle (a space recessed in the vehicle interior direction) on the under surface of the floor of the vehicle.
For example, Japanese Unexamined Patent Application Publication No. 2002-347664 discloses a sub-muffler with a recess formed on the upper side thereof and having curved sides as shown in its FIG. 6. In particular, the sub-muffler is disposed in a recessed part of a floor panel in such a manner that the under surface of the sub-muffler is roughly flush with the under surface of the floor of the vehicle. Further, a recess extending in the vehicle front/back direction is formed at the center in the vehicle width direction on the upper surface of the sub-muffler. Further, a space is formed between the recess and a propeller shaft extending in the front/back direction above the recess and having a circular shape in cross section. This space allows air to flow easily from the front of the vehicle to the back thereof.